honestly, you sound like you don't get hoes and that you are kind of envious of them and their experience.
most men are as faithful as their options. who cares if you know his wife, your loyalty is to him. what did you expect to happen on the trip exactly
just please resist your urge to snitch and stay out of his business.
plenty of men are married to women who annoy the shyt out of them, or who aren't interested in sex anymore. it usually gets worse when kids are involved
they most likely see the guy vacation as a small escape from reality. they have fun for a week or so and move on.
as long as they aint puttin these hoes on no pedestal or wifeying them, who cares.